In general, patients suffering from a symptom of a physical disease take medication to alleviate the symptom.
For example, after a doctor prescribes a medication for a patient, the doctor or patient may confirm whether or not the medication is working.
In recent years, biological sensors which are worn by a user to obtain his/her biological data have been developed. As the biological data, for example, an electrocardiogram (heartbeat interval), pulse wave, body temperature and body movement (acceleration) of the user are obtainable by the sensors.
The biological data obtained by such sensors can be offered to doctors or patients as information necessary to determine whether or not the effect of the taken medication is manifest.
In order for a doctor or patient to accurately determine whether or not the effect of the taken medication is manifest, it is desirable to provide the doctor or patient with biological data which is obtained at all times by a biological sensor.
However, since biological sensors are worn by patients in use as stated above, the sensors need to be reduced in weight and size. Thus, in biological sensors, it is difficult to ensure power necessary to continue to always obtain biological data.